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x.00' ASS(VYATC o C I ATE S INC'. test was approximately 1.5 hours in length. Flowrates, applied vacuums, influent and effluent volatile organic compound (VOC) concentrations, and temperatures were also monitored_during the test; Vapors were extracted using an internal combustion (IC) engine equipped with:a 5-hp blower and a moisture knockout chamber. Two influent vapor samples and one effluent vapor sample were collected during the test. Results and field readings from the short-term vapor extraction are summarized in Tables 4 and 6. During the vapor extraction test, extraction flowrates ranging from 47 to 57 cubic feet per minute (cf n)resulted in vacuums of up to 0.8 inches of water in vadose wells VW-5s and VW-2d located 17 feet from the extraction well. No response was observed in wells MW-1 and VW4, located just 6 to 7 feet from the extraction well. This may have been due to preferential pathways present, in the subsurface or because the wells are screened approximately 8 to 13 feet below the current water table. Vacuums of up to 0.5 inches of water were observed in well MW-3 located 87 feet away which is screened approximately 3 feet below the water table. Laboratory results of the vapor samples indicated that volatile hydrocarbons were detected in the influent samples. Approximately 0.2 pounds of total petroleum hydrocarbons as gasoline (TPHg) was removed during the pilot test. Laboratory results of the effluent vapor sample indicated a destruction efficiency of approximately 70 percent for benzene and over 98 percent for all other constituents analyzed. On November 24, 1998, a short-term air sparge test was initiated by ATC using vapor well VW- 5d as the air injection point, Upon startup of the test, an'air leak was observed in nearby vapor well VW-2s from an apparent crack in the well seat, The test was terminated and provisions were made to abandon well VW-2s. On February 17, 1999, ATC supervised the abandonment of vapor well VW-2s. It was proposed in the workplan to pressure grout the well with neat cement from the bottom of the casing to the surface using a trernie pipe but an unknown obstruction was encountered at 9 feet-bsg and it was not passible to lower the tremie pipe past this depth. A direct push drill rig was used to attempt W:\62574.01\CAP report doa 5